Minimum Club/shooting Age

Hi All, it might seem like a silly question but I can't seem to find the answer on the website. What is the minimum age for membership/shooting? My five year old has been target shooting with BB guns for a while and has surprised me at how accurate he is with a cheap plastic gun. He really enjoys target shooting and I wanted to get him into doing it properly from a distance and with more variety. Any ideas, hints or tips would be gratefully received. Thanks in advance for your help :-) Regards, Shane.